Electric outlet socket and plug



y 22, 1958. M. SAMBONET ELECTRIC OUTLET SOCKET AND PLUG 2 Sheets-Sheet 1Filed July 6, 1954 INVENTOR.

July 22, 1958 M; SAMBONET ELECTRIC OUTLET SOCKET AND PLUG Filed July 6,1954 2 Sheets-Sheet 2 INVENTOR. 4 Q44, {w

Abba-0L f M United State atent O P ELECTRIC OUTLET SQCKET AND PLUG 5Mario Sambonet, Milan, Italy, assiguor to Italb-Rizzieri, Milan, ItalyApplicationiJuly 6, 1954, Serial'No. 441,455 Claiins priority,applicationltaly July 3, 1953 8 Claims; (Cl. 200-51419) Thisinventionrelatestoan electric outlet socket and plug, and moreparticularly itrelatesto a new' and im} proved electricservice' devicecomprising an outlet and a companion plug of the type in which the abovetwo members ofthe device are designed for mechanical interengagementan'd for completing a circuit by'acombination of axial and ofrotational movements impartedto the plugin respect to and inside thesocket member of the device":

It: is an object of'this invention' to provide'a newan'd useft'llelectricoutlet of the above type; having means for instantaneous closingand interruption of the current to: prevent any sparkingbetween thecontacting me'mher's thereof and therefore any inconvenience I anddamage caused'thereby; as-wellf. known bythose skilledin" the 811.

A nother object-of this invention isthe provision of" a" plug; and of a.socket member" of new and improved coir-" struction and designed; tocooperate with said plug for inter-engagement such: aszto'preventaccidental separating oft'thevparts by pulling on. the service cord orfrom other causes; even; if"; the electric" circuit is interrupted, andtherefore: the i provision of w new -and improved socket andizplugzdevice: which :mayabef usefully; used' asa=-p1ain switch device forturnin'gfontandlsotf current with'out sep:arationrandipreventing.accidental-separating of thepa'rts 40 thereof;

Anstillrfurther; object: of. this inventioniis ito provide anewgandtimproved electric: serviceoutlet of ithe chatacter referredto.above;:whichzdoes not tleave-exposerl ahy tefl" minalsswhich:might-be contacted :by; a user; :by:chi"ld'ren':- andother;carelessroneslandl thus :causezshock, injury, andd ma e Another. object\of: this :invention: .is IOPI'OVld an; electr tric, service outletoftthe: type described with-a socket of such construction that asplugr-member partially; inserted thereinto, may be turned ifrom-r a:first: position ini whichsaid membenmay beinserted inrand removed fromsaid socket-to a secondposition; in which said socket and plugzimembersare-mechanically inter-engaged for preventing accidental,separating, of. said; parts, while. the :circuit' is stilhinterrupted,that may be-further.turned from said last-named position to a thirdposition. in which 3' certain contacting members provided thereintocause the circ'ui't to be completed,..that maybe turned backfrom-vsaidthird PQSition to saidwsecond positionv for having-the said"circuitbroken, and thatcomprisesmeans for preventing-Vt accidentaltturning backv of.- then-plug to. said-first- -position-== (in-gwhichthe said plug,is subject to possible removal-)1 wh'enltheinterruption.only of the circuitis .desired.

Afurthervobjectofnthis inventionis to provide ail- '65 electric serviceoutlet of the above-character in which auxiliary contacting 5 devicesand. members are'comprised forv having auxiliary ,Wires connectedthereto, particularly 1 butnot exclusively forhavingthemetallicbodyfofthe servicediapparatus -:.(lamp-,, -radio or 'televisi0nfset,'- electric razor, ,electr'ictrypewriten and soon) ..conne cted tothe ground for safer and better operation thereof.

, 2,844,672 Patented July 2 2, 1958 A still further object of thisinvention is to provide a device of the above character wherein analternative embodiment of the plug member according to theinventioIi-m'aybe used as'a removable wall'la'mp', for example, i. e.forr'erriovably supporting and operating an electric lamp at theposition at which the cooperating socket member is mounted, in a; wallof a'buildin'g, for'e'xample.

After all, it is an object of this invention to provide a new andimproved electric service o'utlet and plug'de vice, the 'parts'of whichare of simple construction, readily assembled and which can readily becoupled and uncoupled.

With the foregoing and other objects" in View which will appear as thedescription proceeds, the" invention consists: of certain novel detailsof construction and combination of parts and membershereinaftermorefully described and pointed out in' the claims, it' beingunderstoodthat'changes andvariou's modifications and alternationsrrr'ay' be made in the construction and in the ar range'ment' of partswithout departing from the spirit of the invention 'as defined in theappended claims.-

In generahl attain the above principal objectsof this invention'byproviding a novel construction comprisinga receptacle having a shapedopening, a plug' ha'vin'g radial contact arms and designed topassth'r'oughsaid shaped opening and intosaid receptacle when in oneof'deter min'edfiist' angular" positions in' respectto said receptacle,resilient contact surfaces inside said receptacle and arranged therein"for being contactedbysaid contact arms as said plug hasbeenturned'insidesaid receptacle from one of "said-first positionsto one'of'detei'niinedthird angular 'positionsfa'n'gula'rly Well spaced from saidfirst-positions; and-foi'bein'g well' de't'ached from at least one ofsaid" contact arms as said plug" is kept at one i of determined secondpositions intermediate to' said first and third positions, means forpreventing' said plu g to be turnedb'ackfronrsaid seco'n'dposition tosaid first position except upon' exerting onsaid' plug a v'oltintarydetermined'action, and a resiliently"supporfednon-conducti've'm'emb'erarranged on at least one of'said-resilient contact surfacesand arranged'in respectto" said surface and to the plugscontact' arm designed tocooperate therewith-for having said-surfaceinstantaneously detached andspaced-from said contact arm and to"beinstantaneously inserted betweensaid contact members; v

These a'nd other advantageous objects and features" of this in'vent'ionwill be fully understood by" a consideration-of the following detaileddescription of a preferred form ofern'bo'diment thereof when taken inconjunction with the accompanying drawings, forming an essentialcomponent 'ofthis specification and wherein like numerals are'empl'oyed'to designate like parts throughout the sev-- eral figu'r"es; and inwhich:

Figured a perspective explodedview of the'plugmember and'the receptaclemember'of an electric service" outlet according to'one embodiment of theinvention,--inwhich the plug 'member'is brought near to the receptaclem'e'nibe'r'in' said first angular position for engagemene thereinto.

Figure2' is a partially sectioned exploded side view of lug-member andreceptacle member," the section being-- takeii 'on'line 2- 2 of Fig. 4.

Figure 3 is a partial side view of a modified form ofembo'dinient'of'aplug member produced according to the inventionand'designedto support and to electrically "con ncta'lamp'j p Figure"4'is a cross-sectionalview of members of Fig'. 2, in which thesaid-plugmember appears as beinginsert'ed' into butnotmechanically andelectrically connected to the said=receptacle'-member;' the saidcross-sectional view he ingjtaken on line 4= 4'of Fig. 2;

Figures 5, 6 and 7 illustrate in a rather diagrammatical manner theoperative parts of members illustrated in Fig. 4, in several variousrespective positions during the turning-on and respectively in the saidthird position and during turning-off of current; and

Fig. 8 is a sectional view of the embodiment shown in Fig. l, thesection being taken on line 8-8 of Fig. 4.

In general, and referring first to Figs. 1 and 2, an electric serviceoutlet device according to this invention comprises a plug member(Fig. 1) having a handle portion 11, preferably of non-conductivematerial, a cylindrical plug portion 12 of non-conductive material andradial contact arms 13 and 14 of conductive material, chromeplated brassfor example, or other suitable metal or metallic alloy known in the art,radially extended from the force end of said plug portion 12, and areceptacle member (Fig. 2) formed by a casing Ill preferably ofnonconductive material, having a shaped front opening comprising acentral circular portion 15 designed to allow passage of saidcylindrical plug portion 12 and radial slots 16 and 17 likewise designedto allow passage of said contact arms 13 and 14 respectively of sameplug.

Preferably, the said contact arms 13 and 14 and the said slot portions16 and 17 are symmetrically shaped, so that the said plug may beinserted in said receptacle in any of two first angular positions at 180one to the other, in which the said arms 13 and 14 are aligned with saidslots 16 and 17 or 17 and 16, respectively. In the forms of embodimentshown, the electric outlet device according to this invention isdesigned for connecting circuits comprising two conductors only, and itis therefore provided with two contact arms only. A three-phase circuithowever may be connected.

In view of the described shaped opening of receptacle member and of thecross-sectional shape of the plug member comprising the said contactingarms, the said plug member 12 may be passed through said opening andinserted in said receptacle by an axially directed movement as indicatedby straight arrows A upon positioning said plug in said first angularposition in respect to said receptacle.

According to the gist of this invention, engaging and contacting membersand parts are provided in said receptacle member for having said plugand receptacle members mechanically connected upon completion of acombined axial and rotational movement indicated by U-shaped arrows B.Said movement comprises firstly a further axial forwarding of the plug12 inside said receptacle, overcoming a slight axial elastic opposition,then a small clockwise rotational movement and then a small axialbackward movement due to said elastic opposition, i. e. the mechanicalconnection of said plug and receptacle member may be actuated byimparting to said plug a socalled bayonet action. As said plug hascompleted said movement B, the electric circuit is still interrupted, i.e. at least one and preferably all contact arms are still kept wellspaced from the contact surfaces arranged inside said receptacle member,and which will be fully described below. For having the circuit closed,a further angular clockwise movement C must be done. By simply turningclockwise and counterclockwise said handle portion 11 of plug member thedescribed device according to the invention may therefore beadvantageously used as a plain switch, as desired for example for havingthe current on or off respectively without mechanical and materialseparation of the plug member from the co-operating socket memher.

In Fig. 2 and partially in Fig. 4 a preferred construction of the plugmember is shown. Referring now to said Figs. 2 and 4, the saidcylindrical plug portion 12 is actuated by a tubular member ofnon-conductive material, of a type currently used in production ofelectrical devices of the kind, having an out-turned flange portion 20made integral to the rear end thereof and designed to be removablyconnected to and to close the front open end of the said handle portion11 of the member, said handle portion being preferably constructed inthe form of a hollow cup-shaped piece of non-conductive material.

Inside said tubular plug portion 12 two metallic parts 21 aresymmetrically constructed and arranged, in Fig. 2 only one of said parts21 being shown. Any one of said parts 21 is provided with a fore radialextension forming the said radial contact arm 13 (or 14), with a rearradial extension 22 bearing a screw 23 for connection to a conductor atthe terminal of the service.

cord leading to the serviced electric supplied apparatus. The said parts21 are kept in the described arrangement and electrically insulated byco-axial core members 24 and 25 of non-conductive material, providedwith longitudinal recesses for said parts 21 and with head outturnedflange forming portions 26 and 27, respectively, on which the endportions 22 and 13, respectively, of said parts 21 abut. Said coremembers 24 and 25 are firmly connected head-to-head in their abuttingrelationship with said parts 21 by an axially arranged metallic rod 28having an enlarged head portion 29 positioned outside of and abutting onthe external flanged end 27 of the core member 25 and having ascrew-threaded portion at its other end, on which a nut 31 may betightly screwed.

As shown particularly in Fig. 2, the said portions and parts 22, 23 and31 are arranged and protected inside the hollow cup-shaped handleforming portion 11 of the plug member of the device. The said portion 11is further provided with a central hole 30 designed for passage of theend portion of a conventional service cord the wire conductors of whichmay be firmly mechanically and electrically connected to the parts 21 bymeans of said screws 23. A third wire conductor comprised in said cord,if any, may be connected to said rod 28 by means of the said nut 31, forgrounding the metallic frame or body of the serviced electricalapparatus. The terminals of said apparatus may therefore be electricallyconnected to the one and respectively to the other of said contact arms13 and 14 and the frame structure or body thereof may be electricallyconnected to the externally arranged head 29 of said rod 28.

According to the alternative form of embodiment of said plug member,shown in Fig. 3, in lieu of said cupshaped handle forming member 11 atubular member 61 of non-conductive material is provided and connectedto an out-turned flange portion 63 of a tubular plug portion 12 havingcontact arms as above described in referring to Fig. 2. By means ofextensions 62 of said flange portion 63 a threaded socket 70 may befirmly supported inside said tubular member 61, said socket beingdesigned for having a conventional electric bulb or glow lamp (notshown) screwed in, according to the present day equipment. Saidscrew-threaded socket 70 is electrically connected to one of saidcontact arms 13 or 14 of the plug portion and the other one of saidcontact arms is electrically connected to a member 64 of conductivemetal or metallic alloy arranged inside and at the bottom of said socket70 and designed for axial abutment and electrical contactingrelationship with the centre terminal of the glow lamp.

Plug members produced according to the invention and constructed asshown in Figs. 2 and 3, respectively, may be alternatively connected foroperation to a receptacle member of the type which will'be now describedin detail and which is shown in Figs. 2 and 4 to 8, in which the partsappertaining to the plug member cooperating therewith may beindiscriminately referred to either of said alternative forms ofembodiment.

According to Figs. 2 and 4, the said receptacle member 10 is formed by acup-shaped piece of non-conductive material, having a front face formingportion 40 at the centre of which the said opening 15-17 is provided.

Said opening is surrounded by an externally screwthreaded collar 41 theaxial dimension of which is less than the spacing betweenthe radiallyextended-1 contact arms 13 and 1 4 of the plug members designed, to,cooperate therewith and; the flange, portion 2,0 or 63' of said plug(see Fig; 2 or- 3 respectively). About said collar 41 an annular member42 aybe screwed on, if desired; for-having a glass orother-inaterial-made 6 tional' covering plate 43; secured upon saidfront face portion 40 of the receptacle body.

The various contact surfaces and; other operative devices which arearranged inside said receptacle body are preferably supported by acircular plate 44 ofnon con ductive; material removably positionedinside said receptaclebody and firmly connected thereto by means or twoor three screws for example, in abutting relationship with an internalstep, 45jprovided in the side walls of said body. Said circular plate.44 aetnates a partition dividing the interior ofsaidbody in aforechambelf (b tween said plate and the face forming portion 40 of saidbody 10) in Whichall contacting and circuit breaking devices are housed,and in arear open chamber inwhich the several means for connection toelectric current sup; ply conductors and to the optional1groundingconduetor are arranged;

In the form of embodirnent shown and as it may be clearly understood bya particular consideration of Figs. 2 and 4, the, inner operativedevices comprise a first resilient contact member 461electrical1yconnected to a first-binding -screw 47, an oppositely arrangedlsec; ondresilient contact member 48 electrically connected to asecondbinding-screw 49 andan auxiliary axially arranged third resilientcontacting member 50 electrically connected to a third auxiliarybinding-serew 51 (Fig, 2 While t a contacting m mbe s. ..and48; a d e,binding-screws 47 and 49v respectively connected thereto are arranged;respectively i insidev and. outsire said f A o mi mb r. 4.4fm. av amp1e. an: s'trnction of the device the said auxiliary contactingmember'SO may be supported outside said partit on;

as: shown in Fig. 2; the saidpartition forming member 44beingprovided'with a central openingthrough which the end" portionofysaid' contactingmember 50 is exposedinside said member 44' facingthe,opening of therecep tacle. I

Said contacting member 50 is made in the form of abent strip ofresilient conductive metal and it is arranged andshaped, as shown inFig. 2, to be contacted} by-theenlarged headportion 29 ofsaid metallicrod 28' of the plug member'as the latter is axially inserted indirection-A (Fig; 1) through the sa-idopeningg15--17';

The-contact between-said parts 50and29-occurs before the; contact arms13 and 14' are fullypassed through the slots- 16 and 17, so that duringtheendportionof theforward motion in direction A of theplug: 12a'resilient opposition by said member 50 occurs. Further; as the: saidplug is nearly fully inserted inthe receptacleand upon connection of rod28ato the-frame or body ofthe serviced apparatus and of binding-screwSl'to ground;

the: said apparatus body onframe is properlygrounded. About the saidopening Hand on the inner face-of collar 41E small projections-w65 'madeintegral with said collar are provided: near the sidesof said slots16'and' 17 (Fig; 2) For having-the said plug'12-'-1'4:free to rotate.inside the receptacle, it is therefore necessary to prosecutetheaxialforwarding-motionof saidplug in direction A, overcoming theopposition-ofresilient contactingsmember 50; until the rear ed-gesofsaid contact arms 13 and 14 may pass over the said projections 65; Assaidconditionissatisfied, saidplug may be-rotatedand 'assaid-contactarms 1'3 and-14 pass-over said projections,- the said plug may:beslightly moved outwardly direction opposed to'A by-thespring action ofsaidcontactingmember SO: Attthispoint the said second-positionisattained, 'asthe two plug vand receptaele=members become--mechani-eallyinter-engaged; and- 'the--saidp u flim y e. r ate n di ec on C"(.t t eid-third po t o ppo ed to kt s condp sitionlin the angular space definedby the abutment of contact arms on said projections65; which act as stopmembers preventing said plug from reaching the said first posii tion inwhich the mechanieal inter-engagementi's,normore made sure and fromwhich said plug maybe drawn, the socket. Whenit is desired' to have the19 .1 remoyed from the receptacle, 'by a slight rotational forcing onthe external handle portion 11' of the plug member, the a act. s 13 andam na-be pa sed ha kion. the projections .65; which are, preferablyround shaped; as shown in Fig; 2. It a more positiye prevention ofacci}dental turning'back ofthe plug member untiij' the filrst position isdesired, saidprojections 65 may be shaped'to have sharp step formingflanks or saw-tooth shaped' se that; a positive pushing action on theplug handle must be exertedfor having t e Saidcontact arms frlee toberotated oyer'said projections.

Preferably, one of the contacting members designed to co-operate withthe contact arms of the 'plugismade for havingthe-saidplug resilientlykept in the said sec: ond and third positionsg and the other one isassociated with the said device provided for havingthe circuit in;stantaneously closed and-1 broken. As shown in Figs. 4 m7; thecontacting. member 46 is; actuated 'by astrip-of resilient conductivemetal and it is provided-with a recess portion52 designed tocomprise theouter'edge of'a contact-arm 14' (or 13) as said plug is rotated tofrom-the firstposition- (Fig-p6), the 'said recess 52 hav{ ing roundedflanks allowing the comprised contact arm to beeasilymoved by impartingalittle rotational force to theplug. Furthen the said-contacting; memberis shaped at both its side portions Gin-respect torecess-52 toabut-onthe contacnarm 14-1 Figst-i and 7") as soon; as thesaid plug isrotatedfrom itsfirst position to' its second position, and toresiliently urge the said armin the second position, i; e. in theabutting relationship with the .inner rflankof oneprojection 651- I Thesecond contacting member 48 is alsoactuated by a; bent. strip of.resilient conductive metal, and isar ranged in opposition-to the; saidfirst contacting member 46; The contacting surfaceof saidfmember-48is-partially; covered by a fiat member 53 made of nonwonduetive materialand provided with; an. opening. 54 positionedto: allow: the passage, ofthe contacti arm. 13; (or 14:) and to. havelhe, outer. edge thereof incontacting-relationshipwith saidmontacting surface astheothercontactrl'4 (or-"- 13) reaches therecess: 52'of othervcontactingmmem'ber 46;,v i. e as .the saidplugis utinitssaid-thirdposition; The said nonsconductiveg member: 53.; is resiliently; urged;against. theta'xis' of the .devicen'by. two symmetrically-ar fingdwcompressionworking coil;springsSS and 56-, or; by: otherpequivalentzspring-:means,-.- and the ends of; same. non-conductive. memhen. 5.3-slidably. .abut' on inclinedsurfaces 59 and 60 of non-conductiveportions 57 and-5'8 respectively; made, integral with the structure-of:the receptacle, preferablywiththe said member-44, the said portions157and: 58.. acting furtheras stop mem-hers for" confining- .the' movementof'sa-id' non-conductive member 53:; urged towards-the devicesaxis bysaid spring means" freely removed from the receptacle by plainpullirigQa-ctionjj exerted'on'thehandleportion thereof 'in a directionop o.- site to A;( Fig.' l). As above descrijl'iedg he condit onofmechanical inter enga'gementoccurs in the said .s'ec,-

'-ond='pos'ition;*in -whieh saidcontact arms have been passed beyond theprojections 55 (Fig. 2). In such position the plug is not subject toaccidental separation from the receptacle, by pulling on the servicecord, for example, or from other causes. Further, in such position theauxiliary grounding circuit is yet closed by the contacting relationshipof enlarged head 29 of rod 28 of plug with the said contacting member 50(Fig. 2) while the power circuit is still interrupted because at leastthe contacting member 48 does not contact any of contact arms 13 or 14of the plug.

Supposing now that the plug is: further rotated for example in directionD (Fig. the contact arm 14 of the plugs contacts one of the sideportions of the contacting member 46 while the other contact arm 13presses on the surface of the said non-conductive member 53 urging itagainst the said contacting member 48. As soon as the edge of saidcontact arm 13 faces the opening 54 of said non-conductive member 53,the said third position is now attained and the latter member may beinstantaneously brought back towards the axis of the device, and theouter edge of said contact arm 13 is therefore instantaneously broughtin full contacting relationship with the contacting member 48 (Fig. 6)and the power circuit is instantaneously completed, as desired. Theseating of opposite contact arm 14 in recess 52 of opposite contactingmember 46 co-operates to maintain the plug in its said third positionand prevents lateral thrusts on the said non-conductive member 53.

Supposing now that turning-01f of the switch actuated by the deviceconstructed according to the invention is desired, and that the plug iscaused by the user to rotate in direction E (Fig. 7) towards its secondposition, the circular motion of the outer edge of contact arm 13 urgesthe said non conductive member 53 to tangentially move leftwards (inrelation to the embodiment shown in Fig. 7) sliding with its left endalong the inclined surface 59, and pressing the coil spring 55 while thesaid outer edge of contact arm still contacts the surface of contactingmember 48 through the said opening 54 i. e. while the power circuit isstill closed. At a certain point of such movements of parts and members,and nearly at the position shown in Fig. 7, by the progressive loweringof said non-conductive member 53 (due to the sliding thereof on surface59) and by the increasing inclination of outer edge of contact arm 13(due to the rotation thereof) the action of the compressed coil spring55 may insert the said non-conductive member 53 between said contact arm13 and said contacting member 48, in a position substantially as shownin Fig. 5, positively spacing said contacting means and materiallypositioning a non-conductive solid material therebetween. Said movementof said non-conductive member 53 is accomplished in a substantiallyinstantaneous manner, and the most desirable instantaneous breaking ofthe circuit and cutting of any spark or are are therefore advantageouslyattained.

Preferably, as shown in the described figures, the above parts aresymmetrically arranged in the device and the third position is made at90 to the first position. In view of such features the electric serviceimplement described may be operated either as a connecting means and asa simple switch by rotating the plug in the one or in the otherdirection, without prejudice of its operation and of its durability. Ofcourse, while in the described figures the said contact arms 13 and 14cooperate with the contacting members 48 and 46.1espectively, saidcooperation may be immaterially accomplished with contacting members 46and 48 respectively.

While I have described and illustrated but one form of embodiment ofthis invention and but one modified embodiment of the plug memberthereof, it will be readily understood that others can, by applyingcurrent knowledge in the art, make several alterations and changes inthe construction of the device according to the invention and of themembers, parts and details thereof, without omitting features thatfairly constitute essential characteristics of this invention as setforth and defined in the appended claims.

Further, an electric service socket and plug produced according to thisinvention might be readily further improved by adding other servicingdevices and/or safety means. For example, the receptacle body may beprovided with two or more sockets designed to co-operate with two ormore plugs, as described. One or more fuses or other safety devicesmight be connected in the power and/or grounding circuits and arrangedin the receptacle and/or in the plug member or members. By applyingcurrent knowledge in the art, a plug member may be devised in which aplug portion, designed to cooperate with a socket member according tothe invention and preferably comprising the described parts 12, 13 and14, may be structurally .and electrically associated at its outerportion (in lieu of portion 11) to a socket for conventional plugs, toadapt the invention to the present day equipment.

Such variations, alterations and additions should and are thereforecomprehended within the meaning and range of equivalents of thisinvention, and what I claim as new and desire to have protected byLetters Patent is:

1. An electric outlet of the type described, comprising a plug memberhaving a cylindrical plug of non-conductive material, conductive contactarms radially extended from the end portion of said cylindrical plug, aconductive head axially arranged at the end of said plug, and bindingmeans to connect said contact arms and said conductive head to powerconductor connected to the serviced apparatus, and respectively to aconductor grounded to the body of the serviced apparatus; and a socketmember comprising a receptacle body of nonconductive material having anopening comprising a circular centre portion and radial slots extendedthereabout for passage of said cylindrical plug and of said contact armswhen in one of determined first angular positions in respect to saidsocket member, a resilient first conductive contacting member connectedto ground positioned at the center of said receptacle body to abut onand to resiliently exert an axial opposition to the said plug on theconductive head thereof as said plug is axially inserted into saidreceptacle body through said opening, power resilient contacting membersconnected to power wires positioned inside said receptacle body aboutthe position of said plug as inserted thereinto and to be contacted bysaid contact arms as said inserted plug is rotated to a third positionangularly spaced from said first position, stop means co-operating withsaid resilient first contacting member for removably keeping saidinserted plug in a second angular position intermediate between saidfirst and said third angular position and in which at least one of saidcontact arms does not contact any power contacting member, anon-conductive member movably supported inside said receptacle body andpositioned between one of said power contacting members and the positionof said plug as inserted in said receptacle body, an opening in saidnon-conductive member designed for passage of one of said contact armsas the said plug is angularly positioned in its said third position andspring means for having said non-conductive member instantaneouslyinserted between said power contacting member and the contact armcontacting thereon as said plug is caused to rotate from said thirdposition towards said second position, and when said contact arm isstill in contacting relationship with said power contacting member.

2. An electrical outlet device, comprising, in combination, a socketmember; a plug member insertable into said socket member in apredetermined first position and turn able therein in inserted positionabout an axis from said first position to second and third positions;locking means provided on said plug member and on said socket member formechanically interlocking said plug member with said in transversedirection from'said axisandmoving in a circular path wh'ensaid-plugmember is tur-ned about said axisaandi-second contact means fixed tosaid'soeket-m'emi berand beingspaced 'from1='saidaxis in' transversedirecration? substantially' thesame distance as said first-coi1tactimeans a-nd being located in -s'aid path 'of said' first contact timeansgisaid second contact ineans beingspaced'from saidrconta'ct-iimeans' in =fsaid first and second positions 1 of said zuplugmemberi and being in "Contact with 'saidfirs't" Contact ameans 'in saidthird position ofsaidplug-rriember-te establish an=electrical contact-withsaid first contact means.

i 3. An 1 electrical outlet device comprising, in com-binati'on; ahollowsocket member ha'ving-a'front plate formed -with an opening Itherethrough and with at least one slot extending: through said plate intransverse direction-from i-said opening; E said front plate havingarear-"-iace';-a plug wmem'ber having a front portion insert-ablethrough- -said rope'ning into said' socket member-in a predeterminedfirst vmosition and turn'able thereinininserted position about an.-axis'from -said first position to second and thir'd posi-:ctionsydocking means fixed 'to said frontpor'tion of said;

.iplugzmember and :proje'cting-in trar1sverse '-dir'ectioi'1*' fromsaidfirst'positiongsaid locking means having in adirection-inormal-torsaid axis 'anoutline matching said s'lot in=said :fr0nt-.plate a" so .--that said locking means are insertable ithrouglr. saidslot in" said first 1 positionof said =plug' mem-f z bemsaid lockingmeans havingan abutting-"face subs'tanrtiallyi normal to said axisabuttingagainst said inner face 'of said::frontplate in said second andthird positions of ="saidft plug member-' to interlock -said plug-1member with r saidzfsocket-i imember; -first contact means 1 fixed to"said iront portion of plug member being spaced in transversedire'ctionrfrom saidaxis and' 'moving'in a 'circiilarpath :wh'emsaidiplug member is turned'in saidstationary socket amemberiabout said Iaxis; and second contact means'fixed rfixed-to said 'socketrriernber andbeing 'spaced from said -axis in transverse direction substantially thesame distance taszsaid first contact means andbei'ng located -in'said'path F ofssaidl'first contact means and spaced from said tfontactsmeansiiin i said" first and second positions 'of -said pl'ug member and'beingiin contact with-saidfirst'contac-t means I in: said" thirdposition of i said -plug member to establish an; electrical contact withsaid first contactmeans.

4. F An electricalv outlet device comprising, in cornbi-nantion; ahollowsocket member having a front plate formed with-an openingtherethroughand with af-le'ast one-slot aextendingrthrough said plate intransversedirectionfrom z=.s'aid';opening-;i said front plate having a -rear*-face; a'pliag member *having a front" portion insertable through-said'topening into said s'ocketm'ember in a 'predetermi'ned first Zposition'. and turnable' therein in inserted position about-=aniaxis='-fromr said firstpo'sition to second "and -third 'pe i-1'tions;::first contact means fixed to said' plugmefnb'e'rand comprisinga lockingand: contact portion projecting' r-in transverse direction tosaid axis from said front portion of said 'plug member,isaid lockingandcontact portion" having in a direction normal to saidaxisanioutlinematching said slot in said front plate'so'tha't said locking and lcontact portion are insertable through said slot in said i first portionof-said-plug membergsaid locking and' c'ontact portion havingan-abutting -face sirbstantially 'h'oi'mal said axis abuttingagainstsaidinner *face of'said front '"plate insaid second and third positions of 1said- "plug m'einber to":interlock-said plug memberwith said socket.zx'nemben' said -locking-- and= contact portion moving in a circularpath when said plug member is turned in said stationary socket memberabout said axis; second contact means fixed to said socket member andbeing spaced from said axis in transverse direction substantially thesame distance as said locking and contact portion of said first contactmeans and being located in said path of said lock- 10 ing' andcontact'po'rtionand spaced from: said 'locliingf'a'nd jcontact-p'oftion'in aid' first and secondpositionsr of stiid plug-member an c'ontact'i'p ortion -in said' third position of said pl g-mem- "16 "about anaxis from saidfi'rst'position to' second'a'nd'third positions; firstcontact-me'an'sfixed' to saidplug'menibcr and 'comprisinga locking and"contact portionprojecting in transverse direction to "said axis from"saidtr'ont 'p'or- 'tion' of said plugfirmber, "said" lockingairdmontact 20 'fp'ortion having inadirectiofi normal tosaid axisianoutline matchingsaid'slot"in said front plate so thatsaiddocking 5 Randcontact-portion are insertablethrouglr said slot insaid *first'po sitionofsaid plug member, saidlo'cki'ng' and contacflportion having anabutting face substantially normal to said axis abutting against'saidfinnerface' of said front *plate' in said secondand'third'positions'of-said plugm'emher to interlock said plug memberWith said socket member, saidlockin'g and-contactportion movingin a'circular "path'when said-plug member is 7 turned in said stationarysocket member about "saidaxis; second "contact m'cans fixed to saidsocket member and beingspaced' ir'om said 'axis'in transverse directionsubstantially thesamedistan'ce "as saidlockingand-contact'portion ofsaid'first contact meansandb'eing locatedinsaid path: offsaidloeking andcontact portion and spaced froml'said locking and contact por'tioninsaid firstand second positions"ofsaid"plug member and bein in contactwitlrsaid locking and contact porti'onin said third-position ofs'aid"plug' member to 40' first retaining means extending from" saidrearface of said fr'ont pl-ate and cooperating with'said abutting face'for retaining said 1 plug member in" saidsecond position;" and second'-=retaining means on one of said contact means and cooperating withtheother of'saidcontact"nieans"forfre- 'taining -said'plug member 'insaid'thi'rd position.

' '6. -An electrical outlet device comprising; in combina- *tion,ahollow socket-member 'having a front plate 'form'ed With an "openingtherethrough and with at leastio'nef slot extendingthrough said' platein"transv'erse direction from saidopening, saidfront:plate"having a rearface; a,pl'i1g r'ner'nbefhaving 'a front" portion 'inse'rtablethrouglifsaid "openinginto said-socket member'in a predeterminedZfi'r'st position- 1 and "turnable thereinin' inserted position aboutarrarns" from said first position to second and third posi- 'tions';' 2first contact 'means' fixed toksaid plugj memberjaiid -"comprising a'locki'ng and contact portionjprojectingin transverse dir'ection to saidaxisfrom saidtfrontcpor'tion of said-plug member, said locking, andcontaetportion having in;'adirectiorr normal itosaid axist'anoutlinematchfi fing said slot i in said front "plate so thatsaidclocking-iand fcontactfpo'rtion are ins'ertable through said 1 slotin? said first; position of said plug member, said locking i and contactfportioril'iaving an. abuttingt face substantiallynormal ljto'said axisabutting.againstsaidinner face of-said' front fplatelin said secondandthird :positions ;of' said-plug member to interlock saidiplug memberwith. said-socket memf'ber,'said'l'dcking"and contact portion moving-ina-circuiar patir"wheni said plug-member is :turned in said;stationary""socket member about said axis; second contact means fixedto said socket member and being spaced from said axis in transversedirection substantially the same distance as said locking and contactportion of said first contact means and being located in said path ofsaid locking and contact portion and spaced from said locking andcontact portion in said first and eing in contact with said locking and1 1 second positions of said locking and contactportion in said thirdpositiontof said plug member to establish an 1 electrical contact withsaid first contact means; and an interrupter plate made of insulatingmaterial and being mounted in said socket member opposite said secondcontact means and extending in a direction tangential to said circularpath, said interrupter plate being formed with an opening therethroughand being movable in said tangential direction between a first positionwhere said opening is between said first and second contact means sosaid contact means may contact each other and a second position wheresaid interrupter plate is located between said contact means to shieldsaid contact means from each other said interrupter plate havingengaging faces cooperating with said locking and contact portion of saidfirst contact means during said turning of said plug member from saidthird to said second position thereof to move said contact plate in saidtangential direction and in the same sense as said plug member; springmeans engaging said interrupter plate from opposite sides and tending tokeep said interrupter plate in said first position, one of said springmeans being deformed during tion to said second position so as to movesaid interrupter plate to said second position thereof at the moment ofcontact disengagement during the turning movement of the plug member.

7. An electrical outlet device comprising, in combination, a hollowsocket member having a front plate formed with an opening therethroughand with at least one slot extending through said plate in transversedirection from said opening, said front plate having a rear face; a plugmember having a front portion insertable through said opening into saidsocket member in a predetermined first position and turnable therein ininserted position about an axis from said first position to second andthird positions; firstcontact means fixed to said plug member andcomprising a locking and contact portion projecting in transversedirection to said axis from said front portion of said plug member, saidlocking and contact portion having in a direction normal to said axis anoutline matching said slot in said front plate so that said locking andcontact .portion are insertable through said slot in said first pathwhen said plug member is turned in said stationary socket member aboutsaid axis; second contact means fixed to said socket member and beingspaced from said axis in transverse direction substantially the samedistance as said locking and contact portion of said first contact meansand being located in said path of said locking and contact portion andspaced from said locking and contact portion in said first and secondpositions of said plug member and being in contact with said locking andcontact portion in said third position of said. plug member to establishan electrical contact with said first contact means; first retainingmeans extending from said rear face of said front plate and cooperatingwith said abutting face for retaining said plug member in said secondposition; second retaining means on one of said contact means andcooperating with the other of said contact means for retaining said plugmember in said third position; and spring means mounted in said socketmember, spaced from said front plate and opposite said opening throughsaid front plate, said spring means ention, a hollow socket memberhaving a front plate formed with an opening therethrough and with atleast one slot extending through said plate in transverse direction fromsaid opening, said front plate having a rear face; a plug member havinga front portion insertable through said opening into said socket memberin a predetermined first position and turnable therein in insertedposition about an axis from said first position to second and thirdpositions; first contact means fixed to said plug member and comprisinga locking and contact portion projecting in transverse direction to saidaxis from said front portion of said plug member, said locking andcontact portion having in a direction normal to said axis an outlinematching said slot in said front plate so that said locking and contactportion are insertable through said slot in said first position of saidplug member, said locking and contact portion having an abutting facesubstantially normal to said axis abutting against said inner face ofsaid front plate in said second and third positions of said plug memberto interlock said plug member with said socket member, said locking andcontact portion moving in a circular path when said plug member isturned in said stationary socket member about said axis; second contactmeans fixed to said socket member and being spaced from said axis intransverse direction substantially the same distance as said locking andcontact portion of said first contact means and being located in saidpath of said locking and contact portion and spaced from said lockingand contact portion in said first and second positions of said plugmember and being in contact with said locking and contact portion insaid third position of said plug member to establish an electricalcontact with said first contact means; first retaining means extendingfrom said rear face of said front plate and cooperating with saidabutting face for retaining said plug member in said second position;second retaining means on one of said contact means and cooperating withthe other ofsaid contact means for retaining said plug member in saidthird position; third contact means centrally located in saidplugmember, extending therethrough and being insulated from said firstcontact means; spring means mounted in said socket member, spaced fromsaid front plate and opposite said opening through said front plate,said spring means made from conductive material and forming fourthcontacting means and engaging said third contact means on said plugmember in inserted position of'the latter to urge said abutting-face ofsaid locking and contact portion against said rear face of said frontplate of said socket member when said plug member is in said second, andthird positions and to establish a contact between'said third and fourthcontact means; and means for grounding said fourth contact'means.

References Cited in the file of this patent UNITED STATES PATENTS978,841 Buckton Dec. 20, 1910 1,593,985 Nielsen July 27, 1926 1,615,726Row Ian. 25, 1927 1,700,437 Hubbell Jan. 29, 1929 2,321,508 Olley et al.June 8, 1943 2,454,221 Seals Nov. 16, 1948 2,646,475 Goodrich et al.July 21, 1953

